The present invention relates to an electric power source breaker which isolates a power supply circuit by means of sublimation of a gaseous actuating reagent, and relates in particular to a compact power source breaker which can forcedly and surely isolate a power supply circuit in case of something unusual such as short circuiting of a wire harness, collision of road vehicles.
FIG. 1 is a systematic diagram showing an example for electronic automobile parts to which a conventional power source breaker is applied. As shown in the figure, the electronic automotive part 100 includes a power supply circuit assembled by connecting a battery 101 of an automobile to each load 102-104 disposed at each location of the automobile using a wire harness 106 with electric wires 105, and a power source breaker 107 intervened in the power supply circuit.
When a circuit-cut signal generated at a power source controller 108 is input in case of something unusual such as short circuiting of a wire harness 106, collision of road vehicles, the power source breaker 107 can stop supplying power from the battery 101 to each load 102-104 etc. through releasing a lock in a manner as described hereinafter according to FIG. 2.
FIG. 2 is a configuration of a solenoid-type power source breaker 107A showing an example of the power source breaker 107 in FIG. 1, and FIG. 2A is a top view and FIG. 2B is a side view. The solenoid-type power source breaker 107A includes a shaft 111, disposed on a base body 110 as shown in FIG. 2A, which is constrained with a lock 113 pressing down the shaft 111 to maintain a terminal 112a and a terminal 112b electrically continued in a connected state, before the circuit-cut signal is input to the solenoid-type power source breaker 107A at the initial state.
At this initial state, electric current in the power supply circuit flows through the rout of the terminal 112a the shaft 111 the terminal 112b, and the terminal 112a and the terminal 112b can supply a large current because of their having the multicontact spring structures.
When the circuit-cut signal is input, by supplying current to a solenoid 115 for drawing a plunger 116 in order to release the lock 113 in a linked state with the shaft 111, pushing forward the shaft 111 by means of pushing force provided by a release spring 114 to make the terminal 112a isolated from the terminal 112b, finally making the terminal 112a electrically open off from the terminal 112b to stop supplying power from the battery 101 to each load 102-104 etc.
However, in the conventional structure shown in FIG. 2, once an impulse is applied to the shaft 111 in the axial direction shown as an arrow A in the figure, the plunger 116 of the solenoid 115 is liable to malfunction to draw a lever 118, and the malfunction may result in a problem of releasing the lock 113 out of a linked state with the shaft 111. There has been also a problem that a need of miniaturization cannot have been coped with due to the use of the solenoid 115.
The present invention, in consideration of the situation described above, aims to provide a power source breaker which can forcedly and surely isolate a power supply circuit in case of abnormalities such as short circuiting of a wire harness, collision of road vehicles, and also has a structure suitable for miniaturizing itself.
In order to achieve the above object, in the present invention at the initial position where a pair of terminals intervened in a power supply circuit is set in a connected state, and a shaft 16 forcedly provided by a release spring 17 with pushing force for sliding movement of itself is linked with a lock 18 forcedly provided by a reset spring 19 with pushing force for constraining sliding movement of the shaft, and a pushing force of a linear actuator 25 is converted into a force in the direction for liberating the linkage with the lock against the reset spring by means of a lock operation plate 20 as a lock liberating means.
According to the present invention, only when the pushing force of the linear actuator 25 goes beyond the pushing force of the reset spring 19, the lock liberating means is actuated, and it can be avoided that the lock may be liberated resulting in the sliding movement of the shaft.
In another embodiment of the present invention, a linear motor has an actuating reagent and an internal gas pressure is changed by vaporization or sublimation of the actuating reagent when the linear motor operates. Because of no adoption of any solenoid, the power source breaker can further be miniaturized, and that will be preferable in order to cut down manufacturing cost.
Further, according to the present invention, since the shaft can be reset immediately after an operation of the shaft, it is easy to make the power supply circuit reset again at an electrically closed state.